{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{5}{c}}
\toprule
&  & \multicolumn{4}{c}{Components} \\  \cmidrule{3-6}
& \multirow{-2}{*}{\shortstack{All \\ APCDs}}  & Cyclone & Bag & Scrubber & ESP \\
& (1) & (2) & (3) & (4) & (5) \\
\midrule \addlinespace
ETS Treatment (=1)              &           0         &      0.0233\sym{*}  &      0.0650\sym{***}&     -0.0151         &     -0.0311         \\
                                &         (.)         &    (0.0134)         &    (0.0231)         &    (0.0310)         &    (0.0207)         \\
\addlinespace\addlinespace
R\textsuperscript{2}            &           .         &        0.66         &        0.68         &        0.71         &        0.75         \\
Control mean                    &        1.00         &        0.95         &        0.85         &        0.67         &        0.12         \\
Plants                          &         276         &         276         &         276         &         276         &         276         \\
\bottomrule
\end{tabular}
}
